Linear guiding device

ABSTRACT

A linear guiding device where noise characteristics are improved by reducing traveling noise and operability of a slider body is smoothed, and where movement braking can be improved by reducing rolling body passage vibration. Crowning  24  with a curved surface having a predetermined curvature radius R is provided on an end section of a rolling body raceway groove  11  of a bearing block  24 . A crowning amount C of the crowning  24  is set to a value C&gt;H max  greater that the value of a maximum elastic deformation amount H max  of a rolling body B elastically deformed in a rolling body rolling path  14  by a preload or an external load. By this, even when a large load acts on a bearing block  2 A or a large installation error occurs by skewing etc., the rolling body B smoothly rolls without an elastic deformation amount of the rolling body B rolling on the end section side of the rolling body raceway groove  11  becoming greater than the crowning amount C. As a consequence, significant worsening of a noise level and impairment of operability can be prevented.

TECHNICAL FIELD

The present invention concerns a linear motion guiding apparatus.

BACKGROUND ART

A linear motion guiding apparatus for linearly guiding an article to beguided while circulating rolling elements such as rollers or ballsinfinitely in the inside is one of important mechanical elements givingsignificant effects on the moving accuracy of semiconductormanufacturing apparatus, super precision fabrication machines, superprecision measuring instruments, etc.

The linear motion guiding apparatus is an apparatus including a guiderail provided with a rail side rolling element raceway groove, and aslider main body in which a slider side rolling element raceway grooveopposed to the rail side rolling element raceway groove is provided andsupported on the guide rail so as to be moveable axially by way ofrolling of a plurality polarity of rolling elements arranged in therolling element rolling channel formed between the slider side rollingelement raceway groove and the rail side rolling element raceway groove.Then, the apparatus includes a rolling element return channel formed inthe slider main body so as to be substantially in parallel with therolling element rolling channel, an end cap attached to both ends in themoving direction of the slider main body to form an outercircumferential circulation groove for a semi-arcuate rolling elementcirculation channel for communicating the end of the rolling elementreturn channel and the end of the rolling element rolling channel, and areturn guide interposed between the end cap and the slider main body toform an inner circumferential circulation groove for the rolling elementcirculation channel at a position opposed to the outer circumferentialcirculation groove.

In a case where rolling elements of the linear motion guiding apparatuscirculate the rolling element rolling channel, the rolling elementcirculation channel, and the rolling element return channel infinitely,periodical fine vibrations (hereinafter referred to as rolling elementpassing vibrations) are generated to greatly effectuate the movingaccuracy of the equipments described above. The rolling element passingvibrations are developed when the rolling elements rolling in therolling element rolling channel (load region) while undergoing load bypre-load or external load are released from the load upon exiting fromthe load region to the rolling element circulation channel (non-loadregion) or applied with additional load upon entrance from the non-loadregion to the load region.

Suppression for the rolling element passing vibrations is conducted byapplying a crowing fabrication to both ends of the slider side rollingelement raceway groove forming the rolling element rolling channelthereby gradually conducting change of load upon exit and entrance ofthe rolling element to and from the load region (for example, in PatentDocument 1).

Patent Document 1: JP04-54310A (FIG. 11, FIG. 15).

However, the linear motion guiding apparatus described above involves aproblem that the operability and the noise level are tended to beworsened in a case where a large load exerts on the slider main body ora large installation error is caused by caulking.

The present invention has been accomplished in view of the foregoingsituations and it intends to provide a linear motion guiding apparatuscapable of attaining the improvement in the noise characteristics by thereduction of the traveling sounds and attaining the smooth operabilityfor the slider main body, as well as capable of improving the movementbraking by the reduction of the rolling element passing vibrations.

DISCLOSURE OF THE INVENTION

As a result of the earnest study made by the present applicant on thenoise characteristics and the operability of a linear motion guidingapparatus, the followings have been found.

That is, it has been found that worsening of the noise characteristicsand the operability of the linear motion guiding apparatus has acorrelation with the amount of crowning for a crowning formed on bothends of the slider side rolling element raceway groove of the slidermain body and the elastic deformation amount of the rolling element. Thecrowing amount is an amount of escape of the slider side rolling elementraceway groove at the contact position between a rolling element and aslider side rolling element raceway groove in the direction of the angleof contact.

Referring further to the correlation between the crowning amount and theelastic deformation amount of the rolling element, the crowning amountis defined in the existent apparatus about to 0.15% or less of adiameter of the rolling element in order to minimize the lowering of theload capacity or since it is based on the value of the pre-load amountand, when a large load exerts on the slider main body, or largeattaching error is caused by caulking or the like, the elasticdeformation amount of the rolling element on the end of the slider siderolling element raceway groove formed with the crowning exceeds thecrowning amount and smooth rolling of the rolling element is hindered toincrease noises. The noises occur more remarkably in a case of setting agap between rows of rolling elements smaller or in a case of interposinga cage piece between the rolling elements to make the pitch between therolling elements constant.

In view of the above, in a linear motion guiding apparatus according toclaim 1 of the present application, includes a guide rail in which arail side rolling element raceway groove is provided to the lateralsurface along an axial direction, a slider main body having a sliderside rolling element raceway groove opposed to the railway side rollingelement raceway groove and supported on the guide rail so as to bemovable axially by way of a plurality of rolling elements arranged in arolling element rolling channel formed between the rail side rollingelement raceway groove and the slider side rolling element racewaygroove, a rolling element return channel provided in the slider mainbody so as to be substantially parallel with the rolling element rollingchannel, an end cap attached to both ends of the slider main body in themoving direction and forming a semicircular outer circumferentialcirculation groove of a rolling element circulation channel forcommunicating the end of the rolling element return channel and the endof the rolling element rolling channel, a return guide interposedbetween the end cap and the slider main body and forming an innercircumferential circulation groove of the rolling element circulationchannel at a position opposed to the outer circumferential circulationgroove, and a crowning disposed on both ends of the slider rollingelement raceway groove, wherein the crowning amount of the crowning isset to a value larger than the maximum elastic deformation amount of therolling element that rolls along the rolling element rolling channel.

Further, according to the invention described in claim 2, in a linearmotion guiding apparatus including a guide rail in which a rail siderolling element raceway groove is provided to the lateral surface alongwith an axial direction, a slider main body having a slider side rollingelement raceway groove opposed to the railway side rolling elementraceway groove and supported on the guide rail so as to be movableaxially by way of a plurality of rolling elements arranged in a rollingelement rolling channel formed between the rail side rolling elementraceway groove and the slider side rolling element raceway groove, arolling element return channel provided in the slider main body so as tobe substantially parallel with the rolling element rolling channel, anend cap attached to both ends of the slider main body in the movingdirection, and forming a semi-arcuate outer circumferential circulationgroove of rolling element circulation channel for communicating the endof the rolling element return channel and the end of the rolling elementrolling channel, a return guide interposed between the end cap and theslider main body and forming an inner circumferential circulation grooveof the rolling element circulation channel at a position opposed to theouter circumferential circulation groove, and a crowning disposed atboth ends of the slider rolling element raceway groove, wherein thecrowning amount of the crowning is set to a value of 1.5% or less of thediameter of the rolling element.

Further, according to the invention described in claim 3, the crowningamount is defined as 0.3% or more of the diameter of the rolling elementin the linear motion guiding apparatus described in claim 2.

Further, according to the invention described in claim 4, the crowningis formed into a curved shape bending at a predetermined radius ofcurvature and the radius of curvature is set to 70 times or more thediameter of the rolling element in a linear motion guiding apparatusdescribed in claim 2 or 3.

Further, according to the invention described in claim 5, a stepelimination portion is provided between the end of the crowning and thegroove end of the inner circumferential circulation groove of the returnguide in contiguous with the end in a linear motion guiding apparatusdescribed in any one of claims 1 to 4.

Further, according to the invention described in claim 6, a horningfabrication is applied at least to a boundary portion between the sliderrolling element groove and the crowning in a linear motion guidingapparatus as described in any one of claim 1 to 5.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a linear motion guiding apparatusaccording to the present invention.

FIG. 2 is a plane view showing a bearing block as a constituent memberof the liner motion guiding apparatus.

FIG. 3 is a view taken along arrow A-A in FIG. 2 showing a firstembodiment according to the invention.

FIG. 4 is a graph for the result of an experiment measuring the changeof the noise level and the change of the ratio of the load capacitywhile changing the amount of the crowning.

FIG. 5 is a graph for the result of experiment measuring the noise levelwhile changing the radius of curvature of the crowning 24.

FIG. 6 is a view showing another embodiment according to the invention.

DESCRIPTION FOR REFERENCES

-   1 guide rail-   2 slider-   2A bearing block (slider main body)-   2B end cap-   10 rolling element raceway groove (rail side rolling element raceway    groove)-   11 rolling element raceway groove (slider side rolling element    raceway groove)-   13 rolling element return channel-   14 rolling element rolling channel-   16 outer circumference circulation groove-   18 return guide-   20 inner circumference circulation groove-   22 rolling element circulation channel-   24 crowning-   26 chamfered portion (step elimination portion)-   28 boundary portion between a rolling element rolling groove and    crowning-   B rolling element-   C crowning amount

BEST MODE FOR PRACTICING THE INVENTION

Preferred embodiments of a linear motion guiding apparatus according tothe present invention are to be described with reference to drawings.

FIG. 1 shows an appearance of a linear motion guiding apparatus. In thelinear motion guiding apparatus, a gate-shaped slider 2 is assembledmoveably over a guide rail 1. Along a ridge where the upper surface andthe lateral surface 1 a of the guide rail 1 cross to each other, arolling element raceway groove 10 comprising a substantially quadrantconcave groove extending in the axial direction is formed. Further, arolling element raceway groove 20 comprising a substantiallysemicircular concave groove in a cross section and extending in theaxial direction is formed also at an intermediate position of both onthe lateral sides 1 a of the guide rail 1.

The slider 2 comprises a bearing block 2A constituting a main body ofthe slider 2 and gate-shaped end caps 2B attached detachably on bothaxial ends thereof and, further, side seals 5 for sealing the openingsof gaps between the guide rail 1 and the slider 2 are attachedrespectively to both ends (end faces for respective end caps 2B) of theslider 2.

As shown in FIG. 2, a rolling element raceway groove 11 having asubstantially semicircular cross section opposing to the rolling elementraceway groove 10 of the guide rail 1 is formed at the corner on theinner lateral surface of both sleeves 6 of the bearing block 2A, while arolling element raceway groove 11 of a substantially semicircular crosssectional shape opposing to the rolling element raceway groove 10 of theguide rail 1 is formed at the central portion on the inner lateralsurface of the sleeve portions 6.

Then, the rolling element raceway grooves 10 of the guide rail 1 and therolling element guide grooves 11 in both sleeve portions 6 of thebearing block 2A form rolling element rolling channels 14 at fourpositions, and the rolling element rolling channels extend in the axialdirection. Further, the slider 2 has rolling element return channels 13each comprising a circular through hole penetrating the upper portionand the lower portion of the thick-walled portion of the sleeves 6 ofthe bearing block 2A penetrating axially in parallel with the rollingelement rolling channel 14.

FIG. 3 shows a first embodiment according to the present invention.

As shown in FIG. 3, the end cap 2B is provided with a semicircularcircumferential circulation groove 16 on the side of the abuttingsurface with the bearing block 2A. Further, a member depicted by areference 18 in FIG. 3 is a return guide interposed between the bearingblock 2A and the end cap 2B, and an inner circumferential circulationgroove 20 is disposed to the outer circumference of the return guide 18at a position corresponding to the outer circumferential circulationgroove 16. The outer circumferential circulation groove 16 and the innercircumferential circulation groove 20 constitute a rolling elementcirculation channel 22 for communicating the rolling element rollingchannel 14 with the rolling element return channel 13, in which therolling element B rolling in the rolling element circulation channel 22is sent from the end point of the rolling element rolling channel 14 tothe start point of the rolling element return channel 13, or from theend point of the rolling element return channel 13 to the start point ofthe rolling element rolling channel 14.

Then, in this embodiment, as shown in FIG. 3, a crowning 24 formed intoa curved surface with a predetermined radius of curvature R is disposedto the end of the rolling element raceway groove 11 of the bearing block2A. The size depicted by a reference C for the crowning 24 is a crowningamount showing the amount of flank of the rolling element rollingraceway groove 21 at the position of contact between the rolling elementB and the rolling element raceway track 11 in the direction of the angleof contact.

Further, the rolling element B represented by a solid line in therolling element rolling channel 14 in FIG. 3 shows a state deformedelastically by a pre-load or external load. Assuming the diameter forthe rolling element B (rolling element shown by a broken line) in a casewhere the deformation load is not applied and assuming the diameter asL1 when the rolling element B suffers from maximum elastic deformationas shown in the solid line, the maximum elastic deformation amountH_(max) for the rolling element B is determined by the followingequation:H _(max) =L1−D  (1)

In this embodiment, the crowning amount C of the crowning 24 is set to avalue larger than the maximum elastic deformation amount H_(max)(C>H_(max)).

In this embodiment, since the crowning 24 is provided at the end of therolling element raceway groove 11, load changes gradually in a casewhere the rolling element B that rolls in the rolling element rollingchannel 14 (load region) while undergoing load by pre-load or externalload is unloaded when it exits from the load region to the rollingelement circulation channel 22 (non-load region) or is applied with anadditional load when it enters from the non-load region to the loadregion, so that the motion braking can be improved due to reduction ofrolling element passing vibrations, and remarkable worsening of noiselevel or worsening of operability can be prevented.

Then, the linear motion guiding apparatus may sometimes be used in astate where loads or moments from various directions exert in acomposite manner or in a state where attaching error is present, and asan allowable value for the extent the composite load or the attachingerror is generally into the applied load in the radial direction basedon the running distance life (flaking life due to fatigue) and theallowable value in this case is defined as 20% or less of the rateddynamic load. In a case where a long life is required, the value isgenerally defined as 10% or less of the rated dynamic load. However,since the crowning amount of the existent crowning disposed to theslider main body of the linear motion guiding apparatus was defined as avalue smaller than the maximum elastic deformation amount of the rollingelement when an external force at 20% for the rated dynamic load exertsin the radial direction, it may possibly worsen the noise level orworsen the operability.

On the contrary, in this embodiment, since the crowning amount C of thecrowning 24 is set to a value larger than the maximum elasticdeformation amount H_(max) for the rolling element B, even in a casewhere a large load exerts on the bearing block 2A or large attachingerror is caused by caulking or the like, and the elastic deformationamount of the rolling element B that rolls on the end of the rollingelement raceway groove 11 is not larger than the crowning amount C andthe rolling element rolls smoothly, remarkable worsening of the noiselevel or worsening of the operability can be prevented.

Further, by using the linear motion guiding apparatus of this embodimentconsidering the compatibility between the noise characteristic and thedurability, in a case where noises occur in the operation of a tablebody before operation, undesired effects on the durability such assignificant reduction of the life by remarkable attaching error orapplied loaded can be forecast, and it is possible to detect theoccurrence of attaching error, etc. before full-scale operation.

Then, a second embodiment according to the present invention is to bedescribed with reference to FIG. 3, FIG. 4, and FIG. 5 described above.

In this embodiment, the radius of curvature R of the crowning 24 was setto 1000 mm and the crowning amount C was set to 0.75% to the diameter Dfor the rolling element B.

Then, when a large attaching error (0.001 rad) was provided in therolling direction to the bearing block 2A and the noise level wasactually measured, it was found that while the increase for the value ofthe noise level was 12 dB (A) in the existent apparatus, it was loweredto 1 dB (A) in this embodiment when compared with a case of no attachingerror.

Further, FIG. 4 is a graph for the result of an experiment of providingan attaching error of 0.001 rad in the rolling direction to the bearingblock 2A and measuring the ratio of the noise level and the loadcapacity while changing the crowning amount C of the crowning 24 (theratio of the load capacity assuming the load capacity of the existentapparatus not provided with crowning as 1 and changing the crowningamount of the apparatus according to this embodiment relative to theexistent apparatus).

In the graph shown in FIG. 4, the abscissa represents the ratio (%) ofthe crowning amount C relative to the diameter D for the rolling elementB.

Generally, since the meaningful difference for the magnitude of soundscan be recognized also by human gap, in a case where the noise level is5 dB (A) or more, it is preferred that the crowning amount C is 0.3% ormore relative to the diameter of the rolling element such that the noiselevel is less than 5 dB (A).

However, as a crowning amount C increases, the load capacity lowers withrespect to a predetermined value as a boundary to lower the life of thelinear motion guiding apparatus. That is, it can be seen that when thecrowning amount C is made larger than a value of 1.5%, the load capacityreduces to less than 80% and the life of the linear motion guidingapparatus lowers abruptly. This is because the crowning length L2 ismade longer when the crowning amount C is increased to a value largerthan 1.5%, whereby the effective length L3 of the rolling elementraceway groove 11 can not be ensured sufficiently and the number ofrolling elements undergoing the load is decreased, so that the loadcapacity of the rolling element rolling channel 14 is less than 80% andthe durability is deteriorated greatly as ½ or less compared with theexistent apparatus. Accordingly, in view of the life of the linearmotion guiding apparatus, when the crowning amount C is defined as 1.5%or less, it is possible to minimize the reduction of the load capacityand ensure the load capacity of 80% or more compared with the existentapparatus.

Accordingly, by setting the crowning amount C within a range from 0.3%to 1.5%, it is possible to provide a linear motion apparatus capable ofimproving the noise characteristics and minimizing the deterioration ofthe durability.

Further, FIG. 5 is a graph for the result of an experiment of providinga larger attaching error (0.001 rad) in the rolling direction to abearing block 2A and measuring the noise level while setting thecrowning amount C relative to the diameter of the rolling element B to0.75% and changing the radius of curvature R for the crowning 24.

As apparent from the graph, the noise level is greatly decreased as theradius of curvature R of the crowning 24 is increased to 70 times ormore the diameter D of the rolling element B. In this case, at a largeradius of curvature R, since the effective length L3 for the rollingelement raceway groove 11 can not be ensured sufficiently because thecrowning length is made longer, it is preferred that the radius ofcurvature R for the crowning 24 is 800 times, the diameter D of therolling element B as the upper limit.

Then, FIG. 6 shows a third embodiment according to the invention.

In this embodiment, a chamfered portion 26 extending in a plane isformed to the end of a crowning 24, and a slight concavity is formedrelative to the groove end of an inner circumferential circulationgroove 20 of the return guide 18 in continuous with the end. The lengthof the chamfered portion 26 is set to less than the diameter for therolling element B. Further, honing fabrication is applied to theboundary 28 between the rolling element raceway groove 11 and thecrowning 24.

In this embodiment, since the chamfered portion 26 is formed at the endof the crowning 24, it is possible to eliminate a large step at thecontinuous portion between the crowning 24 and the inner circumferentialcirculation groove 20 of the return guide 18, absorb the positionaldisplacement for the circulation parts (end cap, return guide) attachedto the bearing end face, or prevent interference with other parts suchas a steel ball (rolling element), and the rolling element B rollssmoothly between the rolling element rolling channel 14, the crowning24, and the rolling element circulation channel 22. Further, sincehoning is applied to the boundary 28 between the rolling element racewaygroove 11 and the crowning 24, the rolling element B rolls smoothlybetween the rolling element rolling channel 14 and the crowning 24.Accordingly, noise characteristics can be improved further.

The chamfered portion 26 described above is not limitative but it may achamfered portion extending in a curved surface. Further, in addition tothe chamfered portion 26, a crowning of another shape may be formed tothe end of the crowning 24, or a portion to be fabricated simultaneouslywith the return guide may be provided.

Further, while the crowning 24 shown in the first to third embodimentshas a shape of a curved surface curved at a predetermined radius ofcurvature R, the same effect can be obtained also by a crowningextending in a planar manner.

Further, while a structure of forming rolling element rolling channels14 each at two positions between both sides of the guide rail 1 and bothsleeves 6 of the bearing block 2A in FIG. 1 and FIG. 2, the samefunction and effect can be provided also by forming the rolling elementrolling channel 14 each at one position.

Further, while the crowning amount C in the embodiment described aboveis flank amount of the rolling element rolling channel 11 at the contactposition in the direction of the angle of contact between the rollingelement B and the rolling element raceway groove 11, in a case wherecrowning fabrication is applied to the two rows of the rolling elementrolling grooves 11 simultaneously for the sake of the fabrication forinstance, the same effect can be obtained by converting the crowningamount C into the amount of change at the groove bottom of the rollingelement rolling groove 11 and controlling the value thereof.

INDUSTRIAL APPLICABILITY

According to the linear motion guiding apparatus of the presentinvention, since a crowning larger than the maximum elastic deformationamount of the rolling element is provided to the end of the slider siderolling element raceway groove, load changes gradually in a case wherethe rolling element B that rolls in the rolling element rolling channel(load region) while undergoing load by pre-load or external load isunloaded when it exits from the load region to the rolling elementcirculation channel (non-load region) or is applied with an additionalload when it enters from the non-load region to the load region, so thatthe motion braking can be improved due to reduction of rolling elementpassing vibrations, and remarkable worsening of noise level or worseningof operability can be prevented. Further, even in a case where a largeload exerts on the slider main body or large attaching error occurs dueto caulking or the like, since the crowning amount is set and theoptimal crowning shape is defined, the rolling element rolls smoothly inthe load region or non-load region, so that remarkable worsening of thenoise level or worsening of the operability can be prevented whilerestricting the reduction of the load capacity.

The present invention is applicable to linear motion guiding apparatusfor guiding an article to be guided linearly in semiconductormanufacturing apparatus, super precision fabrication machines, superprecision measuring instruments, etc.

1. A linear motion guiding apparatus including a guide rail in which arail side rolling element raceway groove is provided to the lateralsurface along an axial direction, a slider main body having a sliderside rolling element raceway groove opposed to the railway side rollingelement raceway groove and supported on the guide rail so as to bemovable axially by way of a plurality of rolling elements arranged in arolling element rolling channel formed between the rail side rollingelement raceway groove and the slider side rolling element racewaygroove, a rolling element return channel provided in the slider mainbody so as to be substantially parallel with the rolling element rollingchannel, an end cap attached to both ends of the slider main body in themoving direction and forming a semicircular outer circumferentialcirculation groove of a rolling element circulation channel forcommunicating the end of the rolling element return channel and the endof the rolling element rolling channel, a return guide interposedbetween the end cap and the slider main body and forming an innercircumferential circulation groove of the rolling element circulationchannel at a position opposed to the outer circumferential circulationgroove, and a crowning disposed on both ends of the slider rollingelement raceway groove, wherein the crowning amount of the crowning isset to a value larger than the maximum elastic deformation amount of therolling element that rolls along the rolling element rolling channel. 2.A linear motion guiding apparatus including a guide rail in which a railside rolling element raceway groove is provided to the lateral surfacealong an axial direction, a slider main body having a slider siderolling element raceway groove opposed to the railway side rollingelement raceway groove and supported on the guide rail so as to bemovable axially by way of a plurality of rolling elements arranged in arolling element rolling channel formed between the rail side rollingelement raceway groove and the slider side rolling element racewaygroove, a rolling element return channel provided in the slider mainbody so as to be substantially parallel with the rolling element rollingchannel, an end cap attached to both ends of the slider main body in themoving direction and forming a semicircular outer circumferentialcirculation groove of a rolling element circulation channel forcommunicating the end of the rolling element return channel and the endof the rolling element rolling channel, a return guide interposedbetween the end cap and the slider main body and forming an innercircumferential circulation groove of the rolling element circulationchannel at a position opposed to the outer circumferential circulationgroove, and a crowning disposed on both ends of the slider rollingelement raceway groove, wherein the crowning amount is defined as 1.5%or less for the diameter of the rolling element.
 3. A linear motionguiding apparatus according to claim 2, wherein the crowning amount isdefined as 0.3% or more for the diameter of the rolling element.
 4. Alinear motion guiding apparatus according to claim 2, wherein thecrowning is formed into a curved surface shape curved at a predeterminedradius of curvature, and the radius of curvature is set to 70 times ormore the diameter of the rolling element.
 5. A linear motion guidingapparatus according to claim 1, wherein a step elimination portion isprovided between the end of the crowing and the groove end of the innercircumferential circulation groove of the return guide in continuouswith the end described above.
 6. A linear motion guiding apparatusaccording to claim 1, wherein honing fabrication is applied at least toa boundary portion between the slider side rolling element groove andthe crowning.
 7. A linear motion guiding apparatus according to claim 3,wherein the crowning is formed into a curved surface shape curved at apredetermined radius of curvature, and the radius of curvature is set to70 times or more the diameter of the rolling element.
 8. A linear motionguiding apparatus according to claim 2, wherein a step eliminationportion is provided between the end of the crowing and the groove end ofthe inner circumferential circulation groove of the return guide incontinuous with the end described above.
 9. A linear motion guidingapparatus according to claim 3, wherein a step elimination portion isprovided between the end of the crowing and the groove end of the innercircumferential circulation groove of the return guide in continuouswith the end described above.
 10. A linear motion guiding apparatusaccording to claim 4, wherein a step elimination portion is providedbetween the end of the crowing and the groove end of the innercircumferential circulation groove of the return guide in continuouswith the end described above.
 11. A linear motion guiding apparatusaccording to claim 2, wherein honing fabrication is applied at least toa boundary portion between the slider side rolling element groove andthe crowning.
 12. A linear motion guiding apparatus according to claim3, wherein honing fabrication is applied at least to a boundary portionbetween the slider side rolling element groove and the crowning.
 13. Alinear motion guiding apparatus according to claim 4, wherein honingfabrication is applied at least to a boundary portion between the sliderside rolling element groove and the crowning.
 14. A linear motionguiding apparatus according to claim 5, wherein honing fabrication isapplied at least to a boundary portion between the slider side rollingelement groove and the crowning.